The present disclosure relates to a method of operating a computer for digital high-capacity printing systems to relay print data, as well as a corresponding computer.
In chapter 15 of the book “Digital Printing, Technology and Printing Techniques of Océ Digital Printing Presses”, 9th Edition, February 2005, ISBN 3-00-001081-5, print servers for high-capacity printers are described. Schematically shown herein is the workflow of a method used in an Océ PRISMAproduction document output management system for communication between two processes of a computer system for transferring print data.
Operating systems (“OS”) are necessary for the operation of computers. These operating systems can include an operating system kernel as their central component. In the kernel, process and data organizations are normally established, upon which build additional software components of the operating system, and possibly of user programs. Requirements for a system kernel can include parallel processing of different tasks, what is known as multitasking; compliance with time-critical limits; and transparency for other applications.
Kernels can be constructed in layers, with the lower, machine-proximal layers forming the basis for those layers disposed above. The upper layers may thereby typically call functions of the lower layers, but not vice versa.
The following layers may be present, from the bottom to the top:                interface layer for hardware (e.g. input/output devices, memory, processors)        layer for memory administration, including virtual main memory        layer for process administration (scheduler)        layer for device administration (device management)        layer for administration of the file systems.        
If all of these functions or layers are integrated into the kernel itself, it is referred to as a monolithic kernel. In a microkernel, portions of this occur in separate processes. User processes also run outside of the kernel, and can operate the functions offered by the kernel to communicate with the aforementioned components of the computer.
Kernel hooks serve as an interface to enable the calling of a routine outside of the kernel at specific locations within a kernel. The use of kernel hooks is described in “Kernel Hook-Prozess-Filter” [“Kernel Hook Process Filter”], Walter Sprenger, IT-security-Special March 2003, Page 39 and the following, for example. With a kernel hook, a program code may be linked into an existing program. A kernel hook normally has unrestricted access to the entire system.
DE 10 2008 037 651 B4 describes a method for communication between two application programs that may be used for communication of print data in printing systems. A synchronization function is hereby used which allows the simultaneous execution of a write process and read process that access the same file. This synchronization function may be linked to the kernel of the operating system by means of a kernel hook.
The exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings.